Cycle Time Calculator

Cooling time is governed by how long it physically takes heat to conduct out of the molten plastic through the mold wall until the part is rigid enough to survive ejection, which scales with the square of wall thickness and depends heavily on the specific material's thermal properties — it's a physics-limited phase, not a machine-speed-limited one. This is why doubling a part's wall thickness can roughly quadruple its cooling time, making wall thickness one of the biggest levers a part designer has over overall cycle time.

Dry cycle time covers mold open/close, ejection, and robot or delay time — pure mechanical motion where no plastic is actually being processed — while fill, pack, and cooling are when the part is genuinely being formed and solidified. Because dry cycle time is mechanical overhead, it's often the easier target for cycle time reduction through faster clamp motion or optimized robot programming, without needing to touch the material or mold cooling design at all.

A cooling percentage that dominant usually points toward opportunities in the mold's cooling circuit design — better-placed cooling channels, conformal cooling that follows the part's geometry more closely, or a lower coolant temperature — rather than in the molding machine's speed or the process settings themselves. Since cooling is thermodynamically driven rather than machine-driven, addressing it usually means mold design or material changes, not just dialing in faster machine motion.

This calculator's cycle time phases describe a single shot regardless of how many cavities the mold has, since fill, pack, cooling, and the mechanical phases all happen once per cycle no matter how many parts that one cycle produces simultaneously. Cavity count instead multiplies your effective parts-per-hour output for a given cycle time, which is exactly the connection the companion part cost calculator uses to convert cycle time into per-part economics.